The present invention is directed to a device for the filtering of a fluid stream with the characteristics of the generic part of patent claim 1 as well as a filter module for the use in such a device.
In order to clean fluid streams, particularly molten plastics, before their processing, it is known to remove the foreign particles from the fluid streams, particularly from the molten plastics, by means of a corresponding filter.
In order realize this filtering of the fluid stream in a continuous manner, it is known for a long time to provide in this case a filtering device which is perfused by the corresponding fluid stream and particularly by the molten plastic. Hereby this filtering device, as far as it is used for the filtering of molten plastics, is arranged downstream of an extruder and upstream of a corresponding tool or a corresponding nozzle.
The DE-AS 15 54 913, for example, describes a corresponding filtering device for an extruder and for injection molding machines, whereby the known device comprises a housing which is provided with a partial fluid duct being perfused by the molten plastic to be correspondingly filtered. In the known device a bolt extends vertically to the flow direction of the fluid in the partial fluid duct, whereby this bolt supports corresponding filters in such a way that the filters are arranged vertically to the flow direction of the molten plastic in the partial fluid duct. By axially shifting of the bolt relatively to the flow direction of the molten plastic it is possible to arrange the filter containing foreign particles and being thus soiled at the outside of the housing, so that correspondingly to that this filter can be cleaned and exchanged. In order not to interrupt the filtering of the molten plastic in this state, the corresponding bolt is provided with a number of further filters which are fixed in the bolt with an axial distance to each other. During the afore mentioned cleaning operation another corresponding filter being supported by means of the same bolt comes into contact with the molten plastic, so that then this molten plastic is filtered by means of this other filter.
A device for the filtering of a fluid stream, particularly for the filtering of a molten plastic, with the characteristics of the generic part of patent claim 1 is known from the DE 195 19 519. Hereby the known device comprises a fluid supply duct and a fluid removal duct, whereby at least one partial fluid duct, namely two partial fluid ducts in the shown embodiment according to the DE 195 19 519, are located between the fluid supply duct and the fluid removal duct. Each partial fluid duct comprises a filter which is arranged mainly vertically to the flow direction of the fluid to be filtered, whereby this filter is supported by means of an axially shiftable bolt being located vertically to the partial fluid duct. As already described above in connection with the DE-AS 15 54 913, this bolt is fixed in a fluid-tight way by a corresponding housing, so that by axially shifting of the bolt the filter being supported by the bolt can be brought into contact with the fluid flowing within the partial fluid duct in order to thus filter the fluid. After the depositing of filtered particles on the filter the correspondingly soiled filter is removed from the fluid by axially shifting the bolt, so that the filter surface can correspondingly be cleaned.
Particularly in the field of plastic processing in which the afore described devices for the filtering of a fluid stream are preferably used, the filter size and the dimensions of the known filtering devices are generally adapted to the momentary needs, whereby the chosen filter size correlates with the plastic to be correspondingly processed and with the soiling of the plastic. Since, however, such filtering devices generally have a relatively long durability, the problem often occurs that the once chosen filter size of the filtering devices turns out to be either too large or too small in the run of the operating time, so that for that reason an optimum production can not be guaranteed anymore.
The present invention has the object of disposing a device of the filtering of a fluid stream, particularly for the filtering of a plastic, of the indicated sort, whereby this filtering device allows a particularly flexible adaptation to the different production conditions.